The present invention relates to a digital audio recorder and player, more particularly to a digital audio recorder and player that automatically stores backup address information.
Digital audio recorders are used as voice memo recorders, and as voice message recorders in portable telephone sets. Some digital audio recorders employ nonvolatile semiconductor memory, such as flash memory, as a recording medium. A single memory device may store several recorded messages, so address information indicating where each message begins and ends is also stored. In a flash memory device, the address information is conventionally stored in a single sector or page, which is erased and rewritten whenever a new message is recorded.
Nonvolatile semiconductor memory devices in general, and flash memory in particular, can tolerate only a limited number of erase-write cycles. Since the address information page is updated frequently, this page may reach its tolerance limit comparatively early, at which point the page no longer stores address information reliably. The user will find that his telephone set or voice recorder can no longer be trusted to record and play messages correctly.
Another problem is that a power interruption or other unforeseen occurrence while the address information page is being rewritten may cause part or all of the address information to be lost, making it impossible to play back the messages recorded in the semiconductor memory device. Address information may also be unintentionally erased by the user, with similar consequences.